1. Field
Aspects of embodiments of the present invention relate to an electrode assembly and a rechargeable battery using the same.
2. Description of the Related Art
Unlike a primary battery that cannot be recharged, a rechargeable battery can be repeatedly charged and discharged. Low-capacity rechargeable batteries are used for portable compact electronic apparatuses such as mobile phones, notebook computers, and camcorders, and high-capacity rechargeable batteries are widely used as a power source for driving a motor of a hybrid vehicle and the like.
A high-power rechargeable battery using a non-aqueous electrolyte with high energy density has been recently developed. For example, the high-power rechargeable battery may be constructed as a high-capacity rechargeable battery having a plurality of rechargeable cells coupled to each other in series such that it can be used as the power supply for driving motors in electric vehicles requiring high power.
In addition, one high-capacity rechargeable battery is commonly formed with a plurality of rechargeable cells coupled to each other in series. The rechargeable battery may have a cylindrical shape, a prismatic shape, a pouch shape, or other shape.
An electrode assembly includes a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes. Here, the separator separates the positive electrode and the negative electrode to prevent a short-circuit therebetween, and absorbs electrolyte required for a battery reaction to maintain high ion conductivity.
When internal temperature of the rechargeable battery increases due to overcharge, the separator may contract or be melted so that a short-circuit may occur between the positive electrode and the negative electrode. When the short-circuit occurs, the internal temperature of the rechargeable battery is rapidly increased so that the rechargeable battery may combust or explode.
The short-circuit may be a short-circuit between a positive active material layer and a negative active material layer, a short-circuit between a positive active material layer and a negative current collector, a short-circuit between a negative active material layer and a positive current collector, or a short-circuit between a positive current collector and a negative current collector. Considering a temperature increase during the short-circuit, it has been determined that a short-circuit between the negative active material layer and the positive current collector is the most dangerous, and a short-circuit between the positive current collector and the negative current collector is the least dangerous.
However, when the positive uncoated region and the negative uncoated region are respectively formed at opposite sides of the electrode assembly, the positive uncoated region and the negative active material layer may possibly be short-circuited rather than the positive and negative current collectors being short-circuited. As described, when the positive uncoated region and the negative active material layer are short-circuited, excessive heat is generated so that the rechargeable battery may combust or explode.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.